One-Pot, Three-Component Borrowing Hydrogen/Cyclization Synthesis of Benzimidazoles

Multicomponent reactions are an efficient toolbox of access to complex compounds, but the development of multicomponent reactions involved in benzimidazole synthesis is still limited. Herein, a one-pot, three-component reaction involving nitrobenzene, benzyl alcohol, and sulfonyl azide was developed for the synthesis of benzimidazoles employing Co-complexes (Salen Co-NHPI) as catalyst, which by self-assembly from salen ligands, organic nitrogen hydroxyl compounds, and CoCl2. Compared with previously reported three-component methods for the construction of benzimidazoles, this method involves a novel hydrogen borrowing/cyclization and can provide a variety of benzimidazole in moderate to excellent yields.